This Is a 5-in-1 Cable Tester.

Supported Cable Types: Tests RJ45, RJ11, BNC, USB, and IEEE 1394 (FireWire) cables. Features: Includes LED indicators for displaying pin/wire status, identifying open circuits, short circuits, and miswiring. Design: Features a handheld, ergonomic design with a detachable remote module for testing cables up to 300 meters long. Power: Typically requires one 9-volt alkaline battery (not included).